Disable user input until handleSignin is complete

[MichielProost]

The user is automatically logged in when the application starts. If he is impatient, he can cause a few errors, for example:

• He immediately goes to the feed: Error = "make a new index for the pair: (isNull, weightedRating)..."
• He immediately goes to the profile screen. He is prompted to log in again, so he does. When 2 log-in procedures run at the same time, yet again, an error occurs. These errors won't cause the application to crash, but it would be nice to avoid them.

How can this be stopped? In the method handleSignIn() there is a 1-2 second pause before the data of the global app_user is fetched. It is in this pause, that the user can cause the errors. An idea would be to wait for the handleSignIn() method to finish. Another idea would be to block the user while appUser.isLoggedIn == false.

Anywho, this requires some investigating.

[Nuytemans-Dieter]

We went for a 'no need to log in'-philosophy so checking for isLoggedIn() is not a good option as it requires a log in. Waiting for handleSignin() to finish is a much better approach. We could use Flutter's AbsorbPointer for this purpose

[MichielProost]

Thank you for all your guidance and wisdom. Much appreciated